PERFUMER&FLAVORIST

The Citrus Trail

Key limes do not come from the Florida Keys.

by Hugo Bovill and Daemmon Reeve, Treatt plc, Bury St. Edmunds, England

ven within the flavor and fragrance industry itself, Ethere is often a certain amount of confusion surround- ing lime and its derivative, lime essential oil. The confusion stems largely from the fact that there are actually two different types of lime, which are most often used in essential oil production — the Persian lime (Citrus latifolia) and the Key lime (Citrus aurantifolia). The cause of clarity isn’t helped by the fact that in Spanish and Portuguese, the languages of several major lime producing countries, the word for lime, “limon”, is actually the same as the word for lemon. The authorities themselves aren’t above the confu- sion either, with several official reports having been re- leased in regards to the quantities of lemon grown in Peru, only for people to realize that the reports were actually referring to Key limes. The exception to this confusion is France, where there are two very different words for the two main varieties — “limette” (Key lime) and “citron vert” (Persian lime). Persian limes.

Persian Limes country. Lime processing generally takes place during the Persian limes are the larger of the two varieties. They quieter periods of orange production and the quantities of grow on almost thornless trees and are seedless and Tahiti lime oil produced can vary from 15-50 tonnes per similar in size and shape to lemons. Grown in significant year. quantities in Mexico and Brazil, where they are called Expressed lime oil from Persian limes is usually ex- Tahiti limes, and to a lesser extent in Florida, the Persian pressed using FMC type extractors or, particularly in Mexico, lime is popular as a fresh fruit and for use in catering due rasping equipment. to its seedless nature. In Key Limes Brazil, the national drink, the “caipirinha”, is a lively The Key lime is much mixture of lime, distilled Key limes do not come smaller and rounder than sugar cane, sugar and ice its Persian cousin. Yellow and accounts for the popu- from the Florida Keys. when fully mature, they are larity of the Persian lime in often harvested while still that country. It’s also grown green. The primary prod- in smaller quantities in Spain“ and Argentina for the local uct derived from Key limes is distilled lime oil, typically fresh fruit markets. produced in countries such as Mexico and Peru. It is Expressed lime oil is generally, but not always, derived obtained by initially pressing the lime to obtain an emul- from the Persian lime. In Brazil, Tahiti lime oil (from the sion of juice and ”oil. The emulsion is then pumped to the cold pressed Persian lime) is a by-product of the produc- stills where the oil is distilled away from the juice by direct tion of lime juice. It is also significantly influenced by steam injection — a process that can take up to 14 h. Much orange production, which is the dominant citrus fruit in the of the flavor of distilled lime oil is actually formed during

28/Perfumer & Flavorist 0272-2666/02/0001-0028$04.00/0—© 2002 Allured Publishing Corp. Vol. 27, January/February 2002 Market Forces The majority of Key limes are processed in Mexico, with a small amount of processing being done in Peru. Peru became a major producer in the 1980s when a priest who had previously worked as a missionary in Mexico trans- ferred to Peru and realised that there was a good local industry growing Key limes. He encouraged a co-opera- tive, Coochul, to invest in basic stills and process distilled lime oil. The arrival of Peru into the lime oil market and subsequent increase in supply (at its peak it produced >180 tonnes of oil), forced prices down from around $15 per pound to $4.50 per pound between 1982 and 1987. At one stage, there were 11 distillers in Peru, but the Mexi- cans fought back, increasing the efficiency of their distill- eries and fruit processing plants. There are now only four or five major distillers in Peru and the price of distilled Key limes. Key lime oil has risen to $7 per pound. It is still a major price reduction however, and compares well with the this process, when the oil is in contact with the naturally hot $3.50 per pound that RC Treatt was selling distilled lime acidic juice. In the West Indian process however, the juice oil for in 1932 and $6 per pound for cold pressed lime oil is largely separated from the settled oil layer after storage in the same year. and prior to distillation. Two types of expressed lime oil can also be produced Cultural Factors from Key limes as a by-product of lime juice processing. There is a very strong demand for fresh fruit in South These are called type A or type B lime oils. Type B is the America, particularly limes. In Mexico, every table and initial product, made by rasping the peel of the fruit using every restaurant will often have numerous condiments pelatrice, or brown-type, equipment. The resulting oil/ derived from Key limes to add color and flavor to many water emulsion is then centrifuged to liberate the cold staple dishes. In Peru, a popular dish is Ceviche — raw fish pressed (CP) lime oil. Subsequently, the whole rasped fruit marinated in lime juice. In effect, the local demand for is crushed, producing a juice/oil emulsion. This in turn is fresh fruit helps subsidise the industrial fruit processing centrifuged to separate the elements, producing a type A industry in these countries. CP oil which is both lighter and has considerably different In contrast, where there is not a high indigenous de- organoleptic characteristics to type B oil due to the fact it mand for fresh fruit the cost of fruit in general is higher and has been in direct contact with the acidic juice. consequently lime cultivation and production is more dif- The citral content of CP Key lime oil is usually around ficult. This has been the case in several African countries, 5 percent, whereas in distilled oil it is typically less than 0.3 such as the Ivory Coast, which in the 1970s was the third percent. In CP oil, !a-terpineol may be present at 0.3 largest lime processor in the world, but where rising fruit percent, but in distilled oil it is common to find as much as prices meant that it became less and less economically 7.5 percent. The two varieties of oil also differ considerably viable. Zanzibar, too, was a successful lime producer, but a in color, distilled oil being a pale yellow/green, even some- combination of disease and political change destroyed the times approaching colorless, whereas CP oil is much darker industry on the island. green. Other Varieties of Lime Growing Key Lime Trees There are many other varieties and hybrids of lime. The rough planting distance for lime trees should typically Thailand, for example, cultivates the Kaffir lime, the leaf be 8 m x 6 m, and they will require significant irrigation of which is used extensively in cooking. The fruit is also throughout the arid times of the season. Key lime trees are processed on a small scale to make distilled lime oil, often grafted on to rootstock, usually rough lemon root- although Kaffir lime oil has a unique flavor and composi- stock, to inhibit disease. However, this tends to result in a tion. Kaffir limes are mid-green color with a rough, lower useful life for the tree of about 15 years, compared bumpy skin compared to the smooth skinned Persian and with 30 years for a pip grown tree. It takes three months for Key limes. The Kaffir lime’s high !a-terpineol content of the fruit to develop from flower to mature lime and while 6 or 7 percent is one of the few similarities with distilled trees will produce some crop after two years, it is not until Key lime oil. it reaches four years that good quality limes are produced India, too, has its own variety, the thin-skinned Kagzi in any significant quantity. Kalan lime which is used extensively in Indian cuisine — lime pickle for example. There is some occasional process-

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ing of distilled lime oil in India but it is used mainly in the local beverage market. Conclusion Lime juice has been a popular flavor with consumers since the sixteenth century. Its health benefits were recognised early on, too. In the eighteenth century its high vitamin C content was recognised as a cheap and effective treatment for scurvy, a fatal disease common among sailors that develops due to a severe shortage of vitamin C. The British government passed an Act in 1867 whereby all British ships had to carry sufficient lime juice for the crew’s daily quota, hence the common American reference to British people, including the authors, as “limeys”. With all the different types of lime available and the corresponding variety in the types of lime oil that are produced, food and beverage producers have a consider- able range of flavoring oils to choose from, depending in their specific requirements. ■ References

Address correspondence to Hugo Bovill/Daemmon Reeve, Treatt plc, Northern Way, Bury St. Edmunds, Suffolk, 1P32 6NL, UK.

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